Antibiotic Resistance - someone please help me understand it

High school biology taught me that when prescribed antibiotics for an infection, you must finish the whole course even if you feel better before the course ends:

Official guidance from the NHS says “it’s essential to finish taking a prescribed course of antibiotics, even if you feel better, unless a healthcare professional tells you otherwise”.

But this new study says that this is just a myth perpetuated by word of mouth:

However, the idea that stopping antibiotic treatment early encourages antibiotic resistance is not supported by evidence, while taking antibiotics for longer than necessary increases the risk of resistance. Without explicitly contradicting previous advice, current public information materials from the US Centers for Disease Control and Prevention (CDC) and Public Health England have replaced “complete the course” with messages advocating taking antibiotics “exactly as prescribed.”

Oxford professor Tim Peto said he was taught about the importance of finishing a course of antibiotics as a medical student, but when he began discussing the origin of the idea with his colleagues, “no one could work out where it came from”.

“This is slow-motion fake news. It went through word of mouth, before the internet,” he told The Independent. “Yes, it’s an urban myth.”

It kind of makes sense that taking antibiotics for any length of time increases antibiotic resistance...

I've been having so many problems with the idea of antibiotic resistance. It seems so much more complicated than people make it out to be. I don't get how antibiotic overuse creates so-called superbacteria. If we think that evolution is the sole cause of it, then it doesn't make sense to say that antibiotics cause resistance, that there are naturally bacteria that exists that is antibiotics has no effect over: in this case, antibiotic use does not cause superbacteria, it merely kills weak bacteria.

A quote from the article article:

Every time a person takes antibiotics, sensitive bacteria (bacteria that antibiotics can still attack) are killed, but resistant bacteria are left to grow and multiply. This is how repeated use of antibiotics can increase the number of drug-resistant bacteria.

I just want to know how resistant bacteria are able to grow and increase? Does the absence of "sensitive" bacteria allow for more... room?

Some bacteria can “neutralize” an antibiotic by changing it in a way that makes it harmless.

Others have learned how to pump an antibiotic back outside of the bacteria before it can do any harm.

Some bacteria can change their outer structure so the antibiotic has no way to attach to the bacteria it is designed to kill.

The lattermost point is the most fascinating- Isn't this an example of Lamarckism rather than evolution via natural selection? If one mechanism of antibiotic resistance is that bacteria can alter their structure to neutralise an antibiotic's effects, and then the bacteria multiplies, hasn't it passed on adaptive traits?

It makes more sense to be that the driving mechanism of antibiotic resistance is Lamarckism. If we just say it's a result of evolution, then resistant bacteria exist naturally, and using antibiotics merely facilitates its growth, rather than creates it.

One thing that's missing from your analysis is how quickly bacteria evolve, because their lifetimes are relatively rapid. When you kill the sensitive bacteria, that does leave more room for resistant bacteria in terms of resources, and so those particular genes that promote resistance become more prevalent in the environment. It's not like you're starting with a set complement of bacterial species and you wind up with all the same species, just in different proportions. The variety of species itself changes in response to environment. So yes you are facilitating rather than directly creating. That's what evolution is.

Now to take that to a particular course of antibiotics, my understanding, based mostly on my research on otitis media, is that you want to balance overuse of antibiotics with actually killing the troublesome bacteria. If you only take, say, a third of the course, you kill the most sensitive bacteria but you leave a slew of bacteria who have been exposed but are not dead. If you hit those same bacteria with another third of the course, you catch then at a different state of cell division when they're more vulnerable, and many of those bacteria are dead and no longer passing on their genes, including some possible Lamarckian reactions to the drug exposure. Lamarckian evolution is a recognizable science now thanks to epigenetics. This does not contradict but rather compliments the 20th century view of the science.

Either way you wind up killing the sensitive bacteria and sparing the resistant bacteria, but you kill more sensitive bacteria over a complete course of antibiotics. And yes many common antibiotic courses have actually gotten shorter because to some degree you want to have sensitive bacteria in the environment.

For the article: I loosely agree with the gist of it as the takeaway is for people to follow physicians' instructions regarding their individual timelines of antibiotic use.

For a couple of questions: If an antibiotic is introduced, the weak bacteria are killed off, allowing resistant bacteria to flourish (more resources and room). An initial resistance of a bacterium comes from a random mutation. From there, other bacteria can acquire resistance from that bacterium by taking in DNA that the dead bacterium ejected, by reproducing, or through cell-to-cell transfer of DNA.

*not a medical biologist*
The point of using antibiotics is to kill enough of the bacteria such that your immune system can easily clean the remainder. As you say, using the antibiotic only kills the bacteria who are weak to that particular drug.... so using it doesn't "create" superbugs. Superbug means a strain of bacteria where most of the bacteria in the population are resistant/immune to the antibiotics.. this means that when you take the antibiotic, it no longer is capable of reducing the population size down to manageable levels.

With this in mind, I think both under- use, and over-use of antibiotics intuitively sensible mechanisms for the proliferation of superbugs.

If you don't finish the course of antibiotics, you are more likely to remain sick (and therefore are more likely to spread the disease to new people).... except when you spread it to new people, the new people are more likely to get a resistant strain of the disease.

On the other hand if you are constantly flooding your body with antibiotics, just about everything in your body is going to be capable of surviving that kind of treatment.

On Lamarck: Bacteria are special in that (some of them? all of them?) can make a live transmission of DNA to one another to boost their evolution speed.... but it's not like the bacteria knows you're about to douse it in penicillin... it doesn't know what penicillin does.... some of the bacteria happen to have a unique shape that provides resistance to the antibiotics.

Violence is never the right answer, unless used against heathens and monsters.

An important piece of this that sometimes gets overlooked is that when a person takes antibiotics as much as 50% of them pass right through the body and get pee'd out. Normal water treatment systems don't really clean antibiotics from the water supply. Combine this with industrial amounts of antibiotics used in agriculture and large quantities of antibiotics end up in oceans and waterways. While studies might be inconclusive regarding whether a single person finishing their antibiotic treatment could cause super resistant bacteria to evolve, creating environments where antibiotics are constantly at 1 million times greater concentration than normal is another thing entirely. Luckily for pharmaceutical companies pollution is mostly self reported, studies on the effects of these chemicals is self funded and publishing negative results is discouraged! I think the reason this myth exists is to push blame onto individuals instead of pharmaceutical companies.

"A new immortal appeared in front of you. Would you like preparations of inception?"

An important piece of this that sometimes gets overlooked is that when a person takes antibiotics as much as 50% of them pass right through the body and get pee'd out. Normal water treatment systems don't really clean antibiotics from the water supply. Combine this with industrial amounts of antibiotics used in agriculture and large quantities of antibiotics end up in oceans and waterways. While studies might be inconclusive regarding whether a single person finishing their antibiotic treatment could cause super resistant bacteria to evolve, creating environments where antibiotics are constantly at 1 million times greater concentration than normal is another thing entirely. Luckily for pharmaceutical companies pollution is mostly self reported, studies on the effects of these chemicals is self funded and publishing negative results is discouraged! I think the reason this myth exists is to push blame onto individuals instead of pharmaceutical companies.

Highlighted agriculture for emphasis.

I live in farmland where the info is pretty well known, but I think many city people aren't aware that most animals are mass-fed antibiotics as a general rule. The amount that goes to animals is more than 3x what humans use. Here is a very good read on the matter.

I live in farmland where the info is pretty well known, but I think many city people aren't aware that most animals are mass-fed antibiotics as a general rule. The amount that goes to animals is more than 3x what humans use. Here is a very good read on the matter.

I had not realized that!

Whenever I would see "raised with no antibiotics" on a label I would get frustrated, because I thought it was some crunchy marketing thing aimed at anti-vaxxers (gluten free eggs! no scary drugs that are actually good for you!) rather than saying anything substantive about the quality of the meat or the animals' quality of life.

Hmmm.

Too bad, Lady Une. You were far too lenient.As a soldier, yes. But as a civilian I lived an austere life.

...the origin of emotional sickness lay in people’s belief that they were their personalities...
"The pendulum of the mind alternates between sense and nonsense, not between right and wrong." ~Carl Jung

I don't want to type much about it atm, but my sister is nearly antibiotic resistant. This just a cautionary tale, I guess.

She has gone into septic shock twice this year: First time was C Diff, which is usually easy to treat with Flagyl; second time was bacterial meningitis, pneumonia, and osteomyolitis. She has had an abscess around the base of her neck for a year. Last week, her right leg went out because the abscess is pinching her nerves. She's being pressured to go a nursing home for three months of rehab, then to an assisted living facility.